HYBRID EVENT: You can participate in person at Valencia, Spain or Virtually from your home or work.

4th Edition of Global Conference on Surgery and Anaesthesia

September 18-20, 2023 | Hybrid Event

September 18 -20, 2023 | Valencia, Spain
GCSA 2022

Andrew Haymet

Andrew Haymet, Speaker at GCSA Conferences 2022
Royal Brisbane and Women's Hospital, Australia
Title : "Mechanical Circulatory Support: Modelling Cannula Dependent Arterial Inflow"

Abstract:

Limb ischemia is a major complication associated with peripheral veno-arterial extracorporeal

membrane oxygenation (VA ECMO). The high velocity jet from arterial cannulae can cause

“sandblasting” injuries to the arterial endothelium, with the potential risk of distal embolization and

end organ damage.                    

Aim

The aim of this study was to identify, for a range of clinically relevant VA ECMO cannulae and flow

rates, any regions of peak flow velocity on the aortic wall which may predispose to vascular injury,

and any regions of low velocity flow which may predispose to thrombus formation.

Methods

A silicone model of the aortic and iliac vessels was sourced and the right external iliac artery was

cannulated. Cannulae ranged from 15 – 21 Fr in size. Simulated steady state ECMO flow rates were

instituted using a magnetically levitated pump (CentriMag pump). Adaptive particle image

velocimetry was performed for each cannula at 3, 3.5, 4 and 4.5 L/min.

Results

For all cannulae, in both horizontal and vertical side hole orientations, the peak velocity on the aortic

wall ranged from 0.3 m/s - 0.45 m/s, and the regions of lowest velocity flow were 0.05 m/s. The

magnitude of peak velocity flow on the aortic wall was not different between a single pair versus

multiple pairs of side holes. Maximum velocity flow on the aortic wall occurred earlier at a lower

pump flow rate in the vertical orientation of distal side holes compared to a horizontal position. The

presence of multiple paired side holes was associated with fewer low velocity flow regions, and

some retrograde flow, in the distal abdominal aorta compared to cannulae with a single pair of side

holes.

Conclusion

From this in vitro visualization study, the selection of a cannula design with multiple versus single

pairs of side holes did not change the magnitude of peak velocity flow delivered to the vessel wall.

Cannulae with multiple side holes were associated with fewer regions of low velocity flow in the

distal abdominal aorta. Further in vivo studies, and ideally clinical data would be required to assess

any correlation of peak velocity flows with incidence of vascular injury, and any low velocity flow

regions with incidence of thrombosis.

Biography:

Dr Andrew Haymet is a Vascular Surgical Registrar at Royal Brisbane and Women’s Hospital, Queensland, Australia, and a PhD Candidate at the University of Queensland. He completed a Bachelor of Engineering (Mechanical)(Hons1) at the University of Sydney, followed by a Bachelor of Medicine/Bachelor of Surgery (MBBS) at the University of Notre Dame, Sydney. He has published several papers in peer-reviewed journals in the fields of vascular surgery, mechanical circulatory support, and vascular biology. Outside of academia and surgery, his interests include road cycling.

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